元器件交易网www.cecb2b.comwww.ti.comActual Size(3,00 mm x 3,00 mm) Actual Size(3,00 mm x 3,00 mm)TPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002ULTRALOW NOISE, HIGH PSRR, FAST RF 100ĆmALOWĆDROPOUT LINEAR REGULATORSFEATURESD100-mA Low-Dropout Regulator With ENDAvailable in 1.8-V, 3.3-V, 4.7-V, and Adj.DHigh PSRR (70 dB at 10 kHz)DUltralow Noise (15 µVRMS)DFast Start-Up Time (63 µs)DStable With Any 1-µF Ceramic CapacitorDExcellent Load/Line TransientDVery Low Dropout Voltage(38 mV at Full Load, TPS79147)DESCRIPTIONThe TPS791xx family of low-dropout (LDO)low-power linear voltage regulators features highpower supply rejection ratio (PSRR), ultralownoise, fast start-up, and excellent line and loadtransient responses in a small outline, SOT23,package. Each device in the family is stable, witha small 1-µF ceramic capacitor on the output. Thefamily uses an advanced, proprietary BiCMOSfabrication process to yield extremely low dropoutvoltages (e.g., 38 mV at 100 mA, TPS79147).Each device achieves fast start-up times(approximately 63 µs with a 0.001 µF bypasscapacitor) while consuming very low quiescentcurrent (170 µA typical). Moreover, when thedevice is placed in standby mode, the supplycurrent is reduced to less than 1 µA. TheTPS79118 exhibits approximately 15 µVRMS ofoutput voltage noise with a 0.1 µF bypasscapacitor. Applications with analog componentsthat are noise sensitive, such as portable RFelectronics, benefit from the high PSRR and lownoise features as well as the fast response time.D5-Pin SOT23 (DBV) PackageDTPS792xx Provides EN OptionsAPPLICATIONSDCellular and Cordless TelephonesDVCOsDRFDBluetooth, Wireless LANDHandheld Organizers, PDADBV PACKAGE(TOP VIEW)INGNDEN1234BYPASSRipple Rejection − dBTPS79133TPS791335OUT10090807060504030RIPPLE REJECTIONvsFREQUENCYVI = 4.3 VCo = 10 µFC(byp) = 0.01 µFHzOUTPUT SPECTRAL NOISE DENSITYvs FREQUENCY0.40.350.30.250.20.150.10.050100IO = 1 mAIO = 100 mAVO = 4.3 VCo = 1 µFC(byp) = 0.1 µFµV/Fixed OptionDBV PACKAGE(TOP VIEW)INGNDEN123654OUTFBBYPASSIO = 10 mA20101001 k10 k100 kf − Frequency − Hz1 M10 MOutput Spectral Noise Density − IO = 100 mAAdjustable Option1 k10 kf − Frequency − Hz100 kPlease be aware that an important notice concerning availability, standard warranty, and use in critical applications of TexasInstrumentssemiconductor products and disclaimers thereto appears at the end of this data sheet.Bluetooth is a trademark owned by the Bluetooth SIG, Inc.PRODUCTION DATA information is current as of publication date. Productsconform to specifications per the terms of Texas Instruments standard warranty.Production processing does not necessarily include testing of all parameters.Copyright 2002, Texas Instruments Incorporated元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002These devices have limited built-in ESD protection. The leads should be shorted together or the device placed in conductive foam during storage or handling to prevent electrostatic damage to the MOS gates.ORDERING INFORMATIONTJVOLTAGE1.2 to 5.5 V−40°C to 125°C1.8 V3.3 V4.7 V(1)The DBVT indicates tape and reel of 250 parts.(2)The DBVR indicates tape and reel of 3000 parts.SOT23(DBV)PACKAGEPART NUMBERTPS79101DBVT(1)TPS79101DBVR(2)TPS79118DBVT(1)TPS79133DBVT(1)TPS79147DBVT(1)TPS79118DBVR(2)TPS79133DBVR(2)TPS79147DBVR(2)SYMBOLPEUIPERIPESIPETIABSOLUTE MAXIMUM RATINGSover operating free-air temperature range unless otherwise noted(1)TPS79101, TPS79118TPS79133, TPS79147Input voltage range(2)Voltage range at ENVoltage on OUTPeak output currentESD rating, HBMESD rating, CDMContinuous total power dissipationOperating virtual junction temperature range, TJOperating ambient temperature range, TA−0.3 V to 6 V−0.3 V to VI + 0.3 V−0.3 V to 6 VInternally limited2 kV500 VSee Dissipation Rating Table−40°C to 150°C−40°C to 85°CStorage temperature range, Tstg−65°C to 150°C(1)Stresses beyond those listed under “absolute maximum ratings” may cause permanent damage to the device. These are stress ratings only, and functional operation of the device at these or any other conditions beyond those indicated under “recommended operating conditions” is not implied. Exposure to absolute-maximum-rated conditions for extended periods may affect device reliability.(2)All voltage values are with respect to network ground terminal.PACKAGE DISSIPATION RATINGBOARDLow K(1)High K(2)PACKAGEDBVDBVRθJC63.75°C/W63.75°C/WRθJA256°C/W178.3°C/WDERATING FACTORABOVE TA = 25°C3.906 mW/°C5.609 mW/°CTA ≤ 25°CPOWER RATING391 mW561 mWTA = 70°CPOWER RATING215 mW308 mWTA = 85°CPOWER RATING156 mW224 mW(1)The JEDEC low-K (1s) board design used to derive this data was a 3-inch × 3-inch, two-layer board with 2-ounce copper traces on top of the board.(2)The JEDEC high-K (2s2p) board design used to derive this data was a 3-inch × 3-inch, multilayer board with 1-ounce internal power and groundplanes and 2-ounce copper traces on top and bottom of the board.RECOMMENDED OPERATING CONDITIONSMINInput voltage, VI (1)Continuous output current, IO (2)2.70NOMMAX5.5100UNITVmAOperating junction temperature, TJ−40125°C(1)To calculate the minimum input voltage for your maximum output current, use the following formula: VI(min) = VO(max) + VDO (max load)(2)Continuous output current and operating junction temperature are limited by internal protection circuitry, but it is not recommended that the device operate under conditions beyond those specified in this table for extended periods of time.2元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002ELECTRICAL CHARACTERISTICS over recommended operating free-air temperature range, (TJ = −40 to 125 °C), VI = VO(typ) + 1 V, IO = 1 mA, EN = 0 V, Co = 10 µF,Co(byp)= 0.01 µF (unless otherwise noted)PARAMETERTPS79101TEST CONDITIONSTJ = 25°C, 1.22 V ≤ VO ≤ 5.2 V0 µA< IO < 100 mA(1),1.22 V ≤ VO ≤ 5.2 VTJ = 25°C0 µA < IO < 100 mA, 2.8 V < VI < 5.5 VTJ = 25°C0 µA < IO < 100 mA, 4.3 V < VI < 5.5 VTJ = 25°C0 µA < IO < 100 mA, 5.2 V < VI < 5.5 V0 µA < IO < 100 mA, TJ = 25°C0 µA < IO < 100 mA0 µA < IO < 100 mA, TJ = 25°CVO + 1 V < VI ≤ 5.5 V, TJ = 25°CVO + 1 V < VI ≤ 5.5 VBW = 100 Hz to 100 kHz,IO = 100 mA, TJ = 25°CC(byp) = 0.001 µFC(byp) = 0.0047 µFC(byp) = 0.01 µFC(byp) = 0.1 µFC(byp) = 0.001 µFC(byp) = 0.0047 µFC(byp) = 0.01 µF2852.2550.050.12321716155367986002.65mAVµsµVRMSMINTYPVO0.98 VO1.81.73.33.2344.74.6061702504.794µAmV%/V3.3661.836V1.02 VOMAXUNITOutput voltageTPS79118TPS79133TPS79147Quiescent current (GND current)Load regulationOutput voltage line regulation (∆VO/VO)(2)Output noise voltage (TPS79118)Time, start-up (TPS79133)Output current limitUVLO thresholdRL = 33 Ω, Co = 1 µF,TJ = 25°CVO = 0 V(1)VCC risingUVLO hysteresisTJ = 25°C, VCC rising100mV(1)The minimum IN operating voltage is 2.7 V or VO(typ) + 1 V, whichever is greater. The maximum IN voltage is 5.5 V. The maximum output currentis 100 mA.(2)If VO≤ 1.8 V then VImin = 2.7 V, VImax = 5.5 V:VV*2.7VOImaxLineregulation(mV)+ǒ%ńVǓ 1000100If VO ≥ 2.5 V then VImin = VO + 1 V, VImax = 5.5 V:VOVImax*VO)1VLineregulation(mV)+ǒ%ńVǓ 100ǒǓǒǒǓǓ 10003元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002ELECTRICAL CHARACTERISTICS continuedover recommended operating free-air temperature range, (TJ = −40 to 125 °C), VI = VO(typ) + 1 V, IO = 1 mA, EN = 0 V, Co = 10 µF,Co(byp)= 0.01 µF (unless otherwise noted)PARAMETERStandby currentHigh level enable input voltageLow level enable input voltageInput current (EN)TEST CONDITIONSEN = VI,2.7 V < VI < 5.5 V2.7 V < VI < 5.5 VEN = VIf = 100 Hz, TJ = 25°C, IO = 10 mAf = 100 Hz, TJ = 25°C, IO = 100 mAf = 10 kHz, TJ = 25°C, IO = 100 mAf = 100 kHz, TJ = 25°C, IO = 100 mAf = 100 Hz, TJ = 25°C, IO = 10 mAf = 100 Hz, TJ = 25°C, IO = 100 mAf = 10 kHz, TJ = 25°C, IO = 100 mAf = 100 kHz, TJ = 25°C, IO = 100 mAIO = 100 mA, TJ = 25°CIO = 100 mAIO = 100 mA, TJ = 25°CIO = 100 mA2.7 V < VI < 5.5 V20.7−1807572457075733750903870mVdB1MINTYP0.07MAX1UNITµAVVµATPS79118Power supply ripple rejectionTPS79133TPS79133Dropout voltage(1)TPS79147(1)IN voltage equals VO(typ) − 100 mV; The TPS79118 dropout voltage is limited by the input voltage range limitations.4元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002FUNCTIONAL BLOCK DIAGRAM—ADJUSTABLE VERSIONVINUVLOCurrentSenseILIMGNDENUVLOThermalShutdownBandgapReference250 kΩVrefR2_SHUTDOWN+R1FBVOUTExternal tothe DeviceBypassVINFUNCTIONAL BLOCK DIAGRAM—FIXED VERSIONVINUVLOGNDENUVLOR2ThermalShutdownCurrentSenseILIM_SHUTDOWN+R1VOUTVINBandgapReference250 kΩVrefBypassTerminal FunctionsTERMINALNAMEBYPASSENFBGNDINOUTADJ435216FIXED43N/A215IOIII/ODESCRIPTIONAn external bypass capacitor, connected to this terminal, in conjunction with an internal resistor, createsa low-pass filter to further reduce regulator noise.The EN terminal is an input which enables or shuts down the device. When EN is a logic high, the devicewill be in shutdown mode. When EN is a logic low, the device will be enabled.This terminal is the feedback input voltage for the adjustable device.Regulator groundThe IN terminal is the input to the device.The OUT terminal is the regulated output of the device.5元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002TYPICAL CHARACTERISTICSTPS79118TPS79133TPS791181.8031.802VO− Output Voltage − VOUTPUT VOLTAGEvsOUTPUT CURRENTVI = 2.8 VCo = 10 µFTJ = 25°CVO− Output Voltage − V3.3033.3023.3013.33.2993.2983.297OUTPUT VOLTAGEvsOUTPUT CURRENT1.82VI = 4.3 VCo = 10 µFTJ = 25°C1.815VO− Output Voltage − V1.811.805OUTPUT VOLTAGEvsJUNCTION TEMPERATUREVI = 2.8 VCo = 10 µF1.8011.81.7991.7981.797020406080IO − Output Current − mA100IO = 1 mA1.81.7951.791.7851.78−40−25−105203550658095110125IO = 100 mA020406080100IO − Output Current − mATJ − Junction Temperature − °CFigure 1TPS79133Figure 2TPS79133Figure 3TPS79118OUTPUT VOLTAGEvsJUNCTION TEMPERATURE3.32VI = 4.3 VCo = 10 µF3.31VO− Output Voltage − VGround Current − µAIO = 1 mA260240220200180160140120GROUND CURRENTvsJUNCTION TEMPERATUREVI = 4.3 VCo = 10 µFHzOUTPUT SPECTRAL NOISE DENSITYvs FREQUENCY0.20.18µV/0.160.140.120.10.080.060.040.0201001 k10 kf − Frequency − Hz100 kIO = 1 mAIO = 100 mAVI = 2.8 VCo = 1 µFC(byp) = 0.1 µF3.3IO = 1 mA3.29IO = 100 mAIO = 100 mA3.283.27−40−25−105203550658095110125100−40−25−105203550658095110125TJ − Junction Temperature − °CTJ − Junction Temperature − °CFigure 4TPS79118Figure 5TPS79118Output Spectral Noise Density − Figure 6TPS79133OUTPUT SPECTRAL NOISE DENSITYvs FREQUENCYHzHz0.25VI = 2.8 VCo = 10 µFC(byp) = 0.1 µFµV/µV/OUTPUT SPECTRAL NOISE DENSITYvs FREQUENCYIO = 0.001 µF10.80.60.40.2010010 kf − Frequency − HzVI = 2.8 VIO = 100 mACo = 10 µFIO = 0.0047 µFIO = 0.1 µFIO = 0.01 µFHz1.2µV/OUTPUT SPECTRAL NOISE DENSITYvs FREQUENCY0.40.350.30.250.20.150.10.050100IO = 1 mAIO = 100 mAVI = 4.3 VCo = 1 µFC(byp) = 0.1 µF0.2IO = 1 mA0.15Output Spectral Noise Density − Output Spectral Noise Density − IO = 100 mA0.10.0501001 k10 kf − Frequency − Hz100 k1 kOutput Spectral Noise Density − 100 k1 k10 kf − Frequency − Hz100 kFigure 76Figure 8Figure 9元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002TYPICAL CHARACTERISTICSTPS79133TPS79133µV(RMS)OUTPUT SPECTRAL NOISE DENSITYvs FREQUENCYHzHz0.40.350.30.250.20.150.10.050100IO = 1 mAIO = 100 mAVI = 4.3 VCo = 10 µFC(byp) = 0.1 µFµV/µV/OUTPUT SPECTRAL NOISE DENSITYvs FREQUENCY21.81.61.41.210.80.60.40.20100IO = 0.01 µFIO = 0.0047 µFIO = 0.1 µFIO = 0.001 µFVI = 4.3 VIO = 100 mACo = 10 µFROOT MEAN SQUARED OUTPUT NOISEvsBYPASS CAPACITANCE7060504030201000.001VO = 1.8 VVO = 3.3 VBW = 100 Hz to 100kHzRMS − Root Mean Squared Output Noise −Output Spectral Noise Density − Output Spectral Noise Density − 1 k10 kf − Frequency − Hz100 k1 k10 k100 k0.010.1f − Frequency − HzC(bypass) − Bypass Capacitance − µFFigure 10TPS79133Figure 11TPS79133Figure 12TPS79213332.52OUTPUT IMPEDANCEvsFREQUENCY80VI = 4.3 VCo = 10 µFTJ = 25°C70VDO− Dropout Voltage − mV6050403020100DROPOUT VOLTAGEvsJUNCTION TEMPERATURE100VI = 3.2 V,Co = 10 µF90VDO− Dropout Voltage − mV8070605040302010−40−25−105203550658095110125TJ − Junction Temperature − °C00DROPOUT VOLTAGEvsOUTPUT CURRENTVI = 3.2 VCO = 10 µFTJ = 125°CTJ = 25°CZo− Output Impedance −ΩIO = 1 mA1.510.5IO = 100 mAIO = 100 mAIO = 10 mATJ = −40°C0101001 k10 k100 k1 M10 M0.020.040.060.080.1f − Frequency − HzIO − Output Current − AFigure 13TPS79101Figure 14Figure 15TPS79118DROPOUT VOLTAGEvsINPUT VOLTAGE120Minimum Required Input Voltage − VIO = 100 mAVDO− Dropout Voltage − mV100806040TJ = −40°C2002.5TJ = 125°CMINIMUM REQUIRED INPUT VOLTAGEvsOUTPUT VOLTAGE5.24.74.23.7TJ = −40°C3.2TJ = 25°C90VI = 3.2 VCo = 10 µFRipple Rejection − dB807060504030202.7102.21.522.533.544.550100RIPPLE REJECTIONvsFREQUENCYIO = 1 mATJ = 125°CIO = 100 mATJ = 25°CVI = 2.8 VCo = 10 µFC(byp) = 0.01 µF1 k10 k100 k1 M10 M33.544.55VI − Input Voltage − VVO − Output Voltage − Vf − Frequency − HzFigure 16Figure 17Figure 187元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002TYPICAL CHARACTERISTICSTPS79118TPS79118TPS79133RIPPLE REJECTIONvsFREQUENCY9080Ripple Rejection − dB706050403020100100IO = 100 mAVI = 2.8 VCo = 1 µFC(byp) = 0.01 µF1 k10 k100 k1 M10 MIO = 10 mARipple Rejection − dB9080RIPPLE REJECTIONvsFREQUENCY100IO = 10 mARipple Rejection − dB9080706050403020100 k1 M10 M10RIPPLE REJECTIONvsFREQUENCYVI = 4.3 VCo = 10 µFC(byp) = 0.01 µF706050403020100100IO = 100 mAIO = 100 mAVI = 2.8 VCo = 1 µFC(byp) = 0.1 µF1 k10 kIO = 10 mA100f − Frequency − Hzf − Frequency − HzFigure 19TPS79133Figure 20TPS79133Figure 211 k10 k100 kf − Frequency − Hz1 M10 MTPS79133RIPPLE REJECTIONvsFREQUENCY10090Ripple Rejection − dB80706050403020101001 k10 k100 kf − Frequency − Hz1 M10 MIO = 10 mAVI = 4.3 VCO = 1 µFC(byp) = 0.01 µFIO = 100 mA90Ripple Rejection − dB8070605040302010VI = 4.3 VCo = 1 µFC(byp) = 0.1 µFIO = 100 mAEnable Voltage − V100RIPPLE REJECTIONvsFREQUENCYOUTPUT VOLTAGE, ENABLE VOLTAGEvsTIME (START-UP)3210C(byp) = 0.001 µFVI = 4.3 VVO = 3.3 VIO = 100 mACo = 1 µFTJ = 25°CIO = 10 mAVO − Output Voltage − V321002040C(byp) = 0.0047 µFC(byp) = 0.01 µF6080100120140160180200t − Time − µs1001 k10 k100 kf − Frequency − Hz1 M10 MFigure 22 − Output Voltage − mVFigure 23TPS79118∆VO − Change In Output Voltage − mVVO − Output Voltage − mVFigure 24TPS79133TPS79118LINE TRANSIENT RESPONSEIO = 100 mACo = 1 µFC(byp) = 0.01 µF100−10LOAD TRANSIENT RESPONSE200−20−40VI = 2.8 VCo = 10 µFLINE TRANSIENT RESPONSE200−20− Input Voltage − VVOCurrent Load − mAVI− Input Voltage − V5.34.3IO = 100 mACo = 1 µFC(byp) = 0.01 µF051015202530t − Time − µsdv0.4V+µsdt354045503.810002.80102030405060708090100t − Time − µsVI02004006008001 k12 k14 k16 k18 k2 kt − Time − µsFigure 25Figure 26Figure 278元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002TYPICAL CHARACTERISTICSTPS79118TPS79133LOAD TRANSIENT RESPONSE∆V − Change InO− Output Current − mA Output Voltage − mVESR − Equivalent Series Resistance − 200−20−40100VI = 4.3 VCo = 10 µFΩTYPICAL REGIONS OF STABILITYEQUIVALENT SERIES RESISTANCE (ESR)vsOUTPUT CURRENT100Co = 0.47 µFVI = 5.5 VTJ = −40 °C to 125°CRegion of Instability1010.1Region ofInstability00.020.040.060.080.10050100150200250300350400450500t − Time − µs0.01IOFigure 28IO − Output Current − AFigure 29TPS79118TPS79118TYPICAL REGIONS OF STABILITYEQUIVALENT SERIES RESISTANCE (ESR)vsOUTPUT CURRENTΩ100Co = 1 µFVI = 5.5 VTJ = −40 °C to 125°CRegion of InstabilityΩESR − Equivalent Series Resistance − ESR − Equivalent Series Resistance − TYPICAL REGIONS OF STABILITYEQUIVALENT SERIES RESISTANCE (ESR)vsOUTPUT CURRENT100Co = 10 µFVI = 5.5 VTJ = −40 °C to 125°CRegion of Instability1010110.1Region of Stability0.0100.020.040.060.080.1IO − Output Current − A0.1Region of Stability0.0100.020.040.060.080.1IO − Output Current − AFigure 30Figure 319元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002APPLICATION INFORMATIONThe TPS791xx family of low-dropout (LDO) regulators have been optimized for use in noise-sensitivebattery-operated equipment. The device features extremely low dropout voltages, high PSRR, ultralow outputnoise, low quiescent current (170 µA typically), and enable-input to reduce supply currents to less than 1 µAwhen the regulator is turned off.A typical application circuit is shown in Figure 32.TPS791xxVI1IN45BYPASSOUT0.1 µF3ENGND2VO0.01 µF+1 µFFigure 32. Typical Application CircuitEXTERNAL CAPACITOR REQUIREMENTSA 0.1-µF or larger ceramic input bypass capacitor, connected between IN and GND and located close to theTPS791xx, is required for stability and to improve transient response, noise rejection, and ripple rejection. Ahigher-value electrolytic input capacitor may be necessary if large, fast-rise-time load transients are anticipatedand the device is located several inches from the power source.Like all low dropout regulators, the TPS791xx requires an output capacitor connected between OUT and GNDto stabilize the internal control loop. The minimum recommended capacitance is 1 µF. Any 1 µF or larger ceramiccapacitor is suitable. The device is also stable with a 0.47 µF ceramic capacitor with at least 75 mΩ of ESR.The internal voltage reference is a key source of noise in an LDO regulator. The TPS791xx has a BYPASS pinwhich is connected to the voltage reference through a 250-kΩ internal resistor. The 250-kΩ internal resistor,in conjunction with an external bypass capacitor connected to the BYPASS pin, creates a low pass filter toreduce the voltage reference noise and, therefore, the noise at the regulator output. In order for the regulatorto operate properly, the current flow out of the BYPASS pin must be at a minimum because any leakage currentcreates an IR drop across the internal resistor thus creating an output error. Therefore, the bypass capacitormust have minimal leakage current.For example, the TPS79118 exhibits approximately 15 µVRMS of output voltage noise using a 0.1 µF ceramicbypass capacitor and a 1 µF ceramic output capacitor. Note that the output starts up slower as the bypasscapacitance increases due to the RC time constant at the bypass pin that is created by the internal 250 kΩresistor and external capacitor.BOARD LAYOUT RECOMMENDATION TOIMPROVE PSRR AND NOISEPERFORMANCETo improve ac measurements like PSRR, output noise, and transient response, it is recommended that theboard be designed with separate ground planes for VIN and VOUT, with each ground plane connected only atthe ground pin of the device. In addition, the ground connection for the bypass capacitor should connect directlyto the ground pin of the device.10元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002POWER DISSIPATION AND JUNCTION TEMPERATURESpecified regulator operation is assured to a junction temperature of 125°C; the maximum junction temperatureshould be restricted to 125°C under normal operating conditions. This restriction limits the power dissipationthe regulator can handle in any given application. To ensure the junction temperature is within acceptable limits,calculate the maximum allowable dissipation, PD(max), and the actual dissipation, PD, which must be less thanor equal to PD(max).The maximum-power-dissipation limit is determined using the following equation:Tmax*TAP+JD(max)RqJAWhere:TJmax is the maximum allowable junction temperature.RθJA is the thermal resistance junction-to-ambient for the package, see the dissipation rating table.TA is the ambient temperature.The regulator dissipation is calculated using:PD+V*V IIOO(1)ǒǓ(2)Power dissipation resulting from quiescent current is negligible. Excessive power dissipation triggers thethermal protection circuit.PROGRAMMING THE TPS79101 ADJUSTABLE LDO REGULATORThe output voltage of the TPS79101 adjustable regulator is programmed using an external resistor divider asshown in Figure 33. The output voltage is calculated using:VWhere:Vref = 1.2246 V typ (the internal reference voltage)Resistors R1 and R2 should be chosen for approximately 50-µA divider current. Lower value resistors can beused for improved noise performance, but the solution consumes more power. Higher resistor values shouldbe avoided as leakage current into/out of FB across R1/R2 creates an offset voltage that artificiallyincreases/decreases the feedback voltage and thus erroneously decreases/increases VO. The recommendeddesign procedure is to choose R2 = 30.1kΩ to set the divider current at 50 µA, C1 = 15 pF for stability, andthen calculate R1 using:R1+O+V 1)R1refR2ǒǓ(3)ǒO*1VrefVǓ R2(4)In order to improve the stability of the adjustable version, it is suggested that a small compensation capacitorbe placed between OUT and FB. For voltages <1.8 V, the value of this capacitor should be 100 pF. For voltages>1.8 V, the approximate value of this capacitor can be calculated as:(3 10*7) (R1)R2)C1+(R1 R2)(5)The suggested value of this capacitor for several resistor ratios is shown in the table below. If this capacitor isnot used (such as in a unity-gain configuration) or if an output voltage < 1.8 V is chosen, then the minimumrecommended output capacitor is 2.2 µF instead of 1 µF.11元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002TPS79101VI1 µF≥2 V≤0.7 V0.01 µFENOUTC1VOR11 µFINOUTPUT VOLTAGEPROGRAMMING GUIDEOUTPUTVOLTAGE2.5 V3.3 V3.6 VR2R1R2C122 pF15 pF15 pF31.6 kΩ30.1 kΩ51 kΩ30.1 kΩ59 kΩ30.1 kΩBYPASSFBGNDFigure 33. TPS79101 Adjustable LDO Regulator ProgrammingREGULATOR PROTECTIONThe TPS791xx PMOS-pass transistor has a built-in back diode that conducts reverse current when the inputvoltage drops below the output voltage (e.g., during power down). Current is conducted from the output to theinput and is not internally limited. If extended reverse voltage operation is anticipated, external limiting mightbe appropriate.The TPS791xx features internal current limiting and thermal protection. During normal operation, the TPS791xxlimits output current to approximately 400 mA. When current limiting engages, the output voltage scales backlinearly until the overcurrent condition ends. While current limiting is designed to prevent gross device failure,care should be taken not to exceed the power dissipation ratings of the package or the absolute maximumvoltage ratings of the device. If the temperature of the device exceeds approximately 165°C, thermal-protectioncircuitry shuts it down. Once the device has cooled down to below approximately 140°C, regulator operationresumes.12元器件交易网www.cecb2b.comwww.ti.comTPS79101, TPS79118TPS79133, TPS79147SLVS325C − MARCH 2001 − REVISED MAY 2002MECHANICAL DATADBV (R-PDSO-G5) PLASTIC SMALL-OUTLINE0,95540,500,300,20M1,701,503,002,600,15 NOM13,002,803Gage Plane0,250°−8°0,550,35Seating Plane1,450,950,05 MIN0,104073253-4/F 10/00NOTES:A.B.C.D.All linear dimensions are in millimeters.This drawing is subject to change without notice.Body dimensions do not include mold flash or protrusion.Falls within JEDEC MO-17813元器件交易网www.cecb2b.comTPS79101, TPS79118TPS79133, TPS79147www.ti.comSLVS325C − MARCH 2001 − REVISED MAY 2002MECHANICAL DATADBV (R-PDSO-G6) PLASTIC SMALL-OUTLINE0,956X0,500,250,20M1,701,503,002,600,15 NOM13,002,803Gage Plane0,250°−8°0,550,35Seating Plane1,450,950,05 MIN0,104073253-5/F 10/00NOTES:A.B.C.D.E.All linear dimensions are in millimeters.This drawing is subject to change without notice.Body dimensions do not include mold flash or protrusion.Leads 1, 2, 3 are wider than leads 4, 5, 6 for package orientation.Pin 1 is located below the first letter of the top side symbolization.14元器件交易网www.cecb2b.com
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